BACKUP DEVICE

摘要

A backup server of a backup site receives a message transmitted by multicast from a job server of a primary site, extracts job data, distributes the data for respective job servers when storing the data in a backup database. Here, a sequence number contained in the message is added to the job data which is stored in the backup database. By detecting a lack of a sequence number, it is possible to detect which job data is missing. Even when job data is missing, the backup server does not request the job server of the primary site to perform retransmission but directly requests the data server of the primary site to transmit the job data.